The present disclosure relates to a control device of an energy storage system, and more particularly, to a control device of an energy storage system considering a power reserve margin.
When managing a power network, the biggest issue of load usage patterns is a peak load. When a constant load is always used, it is possible to stably supply power because the load is usually applied to a power generation plan. However, when a load representing low power consumption suddenly consumes a lot of power, there may be a limitation in that a power network becomes instable because demand and supply do not match. In this context, there is also a limitation in that a generator needs to always prepare for generating as much as peak power in order to bear the usage of all loads. That is, when generation fails to bear peak consumption, a power network itself may become instable, and when the generation is sufficiently great to be capable of bearing peak consumption, there may be a matter with excessive facility investment.
FIGS. 1 and 2 are block diagrams of a control device of a typical energy storage system.
Referring to FIGS. 1 and 2, the control device of the typical energy storage system calculates a duty ratio for controlling the operation switch of an energy storage system based on active power P, reactive power Q, and the reference values of the active power and reactive power Pref and Qref, and controls the operation of the energy storage system based on the calculated values.
The control device of the energy storage system in FIG. 2 is configured by adding a droop controller to the control device in FIG. 1. That is, by adding the droop controller to a controller based on active power and reactive power in FIG. 1, the control device performs a method of calculating a control coefficient by further using a voltage and frequency. It is possible to use reactive power and active power constants, and voltage and frequency constants capable of being calculated at the droop controller to calculate a switching control coefficient based on reactive power, active power, frequency and voltage values to control a switch for the operation of the energy storage system.
Since the operation control of the energy storage system according to the above-described method is a configuration for controlling the charging and discharging of the energy storage system based on coefficient values simply, there is a limitation in that it is difficult to prepare for power shortage capable of occurring in a particular season or an error in power supply. Also, there is a limitation in calculating the control coefficient for the operation of the control device for energy charging and discharging operations depending on the time zone or the situation.